﻿#region Copyright & licence

// This file is part of Refix.
// 
// Refix is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
// 
// Refix is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Lesser General Public License for more details.
// 
// You should have received a copy of the GNU Lesser General Public
// License along with Refix.  If not, see <http://www.gnu.org/licenses/>.
// 
// Copyright (C) 2010-11 David Musgrove and others.

#endregion

using System;
using System.Collections.Generic;

namespace Refix.Core.Repository
{
    public class VersionNumberComparer : IComparer<string>
    {
        public int Compare(string x, string y)
        {
            string[] xParts = x.Split('.');
            string[] yParts = y.Split('.');
            int index = 0;
            while (true)
            {
                int xPart;
                bool xPartIsNumeric = int.TryParse(xParts[index], out xPart);
                int yPart;
                bool yPartIsNumeric = int.TryParse(yParts[index], out yPart);
                int trialResult;
                if (xPartIsNumeric && yPartIsNumeric)
                {
                    trialResult = xPart.CompareTo(yPart);
                }
                else
                {
                    trialResult = xParts[index].CompareTo(yParts[index]);
                }
                if (trialResult != 0)
                {
                    return trialResult;
                }
                ++index;
                if (index >= xParts.Length && index < yParts.Length)
                {
                    return 1;
                }
                if (index >= yParts.Length && index < xParts.Length)
                {
                    return -1;
                }
                if (index >= xParts.Length)
                {
                    return 0;
                }
            }
        }
    }
}